I used to swear by the Spit5, but more recently, the Ki43. It's slower than almost everything except a Stuka, has limited ammo and only 2 50 cals, but it'll turn around twice in the same time/space as even other turn fighters will turn once. At least it feels that way.
Getting mobbed, it can be very elusive, 1v1 against a good E fighter, you're in big trouble, fortunately though most of the rest of the MA can't seem to resist trying to turn fight with it after a couple of misses doing BnZ on it (again, it's elusive), and once that happens, it's easy to start poking little 50 cal holes and hoping something falls off.